This invention relates to a process timing and controlling system for use in photographic darkrooms involving multiple timing and control process steps. Photographic darkroom procedure typically involves a combination of automated and manual processes. On the one hand, automatic timing is desired for uniform exposure enlargement, developing and agitation steps. For this purpose a variety of darkroom timers have been developed which may be programmed to measure and indicate the time remaining in each process step.
On the other hand, operator intervention is a prime feature of darkroom procedure. The worker must manually transfer a negative or print to and from the enlarger or between the various baths. Transfer times vary and are not easily monitored. Further, the operator may wish to extend or abbreviate the various process steps in order to produce a particular contrast or other print quality.
Present darkroom timers and process controllers lack the flexibility required because of operator intervention in the darkroom. Once programmed time is set, it cannot be altered without entirely reprogramming the timer. This may result in great inconvenience. Time is wasted. The reduced lighting of the darkroom hinders using a full keyboard to modify the program. Erroneous key entries are likely to result.
The operator's constant moving around the darkroom to various operating positions also creates problems. At present, means for remotely controlling darkroom process timing and controlling programs as well as remotely displaying the time remaining in each step are lacking. These features would permit the operator control over the timing and controlling of darkroom processes at remote sites.
Additionally, present systems are programmable in one channel only. A multiple channel system would permit even greater flexibility. For example, the "wet" processes could be programmed entirely separately from the "dry" steps.
Present use of relays in the darkroom is also inconvenient. Normally a relay box is plugged into a wall outlet and the appliance to be controlled is plugged into the relay. This is wasteful of the wall plug (1-to-2 or 1-to-3 adapters are necessary to re-plug in non-switched devices), the cord to the appliance may need an extension, and with several relay boxes connected, there may be an immediate shortage of outlets and extensions.